• Aucun résultat trouvé

Residue and Dietary Risk Assessment of Chiral Cyflumetofen in Apple

N/A
N/A
Protected

Academic year: 2021

Partager "Residue and Dietary Risk Assessment of Chiral Cyflumetofen in Apple"

Copied!
13
0
0

Texte intégral

(1)

Article

Residue and Dietary Risk Assessment of Chiral

Cyflumetofen in Apple

Jing Guo1,†, Minmin Li1,2,†, Yongguo Liu3, Fengzhong Wang1, Zhiqiang Kong1,*,

Yufeng Sun1, Jia Lu1, Nuo Jin1, Yatao Huang1, Jiameng Liu1, Frédéric Francis2and Bei Fan1,* 1 Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of

Agro-products Quality and Safety Control in Storage and Transport Process/Laboratory of Agro-products Quality Safety Risk Assessment, Ministry of Agriculture, Beijing 100193, China; 13520410391@163.com (J.G.); liminmin@caas.cn (M.L.); wangfengzhong@sina.com (F.W.); sunyufeng@caas.cn (Y.S.);

luciatime@foxmail.com (J.L.); jinnuo@caas.cn (N.J.); huangyatao@caas.cn (Y.H.); ljiam88@sina.com (J.L.) 2 Functional and Evolutionary Entomology, Gembloux Agro-Bio-Tech, University of Liège,

Passage des Déportés 2, 5030 Gembloux, Belgium; frederic.francis@ulg.ac.be

3 Beijing Key Laboratory of Flavor Chemistry, Beijing Technology and Business University (BTBU), Beijing 100048, China; liuyg@th.btbu.edu.cn

* Correspondence: kongzhiqiang@caas.cn (Z.K.); fanbeicaas@163.com (B.F.); Tel.: +86-10-6281-5969 (Z.K.); +86-10-6281-5969 (B.F.)

† These authors contributed equally to this work.

Academic Editors: Jacek Namie´snik and Justyna Płotka-Wasylka Received: 3 April 2018; Accepted: 29 April 2018; Published: 2 May 2018



 Abstract:Ultra-performance convergence chromatography is an environmentally-friendly analytical method that uses dramatically reduced amounts of organic solvents. In addition, a robust and highly sensitive chiral separation method was developed for the novel chiral acaricide cyflumetofen by using ultra-performance convergence chromatography coupled with tandem mass spectrometry, which shows that stereoisomer recoveries determined for various apple parts ranged from 78.3% to 119.9%, with the relative standard deviations being lower than 14.0%. The half-lives of (−)-cyflumetofen and (+)-cyflumetofen obtained under 5-fold applied dosage equal to 22.13 and 22.23 days, respectively. For 1.5-fold applied dosage, the respective values were determined as 22.42 and 23.64 days, i.e., the degradation of (−)-cyflumetofen was insignificantly favored over that of its enantiomer. Importantly, cyflumetofen was unevenly distributed in apples, with its relative contents in apple peel, peduncle, and pomace equal to 50%, 22%, and 16%, respectively. The proposed method can be used to efficiently separate and quantify chiral pesticide with advantages of a shorter analysis time, greater sensitivity, and better environmental compatibility. Additionally, the consumption of apples with residue of cyflumetofen did not pose a health risk to the population if the cyflumetofen applied under satisfactory agricultural practices after the long-term dietary risk assessment.

Keywords: chiral cyflumetofen; enantioselective degradation; distribution; ultra-performance convergence chromatography; dietary risk assessment

1. Introduction

Apples are one of the major fruits in the world, with China being the largest producer [1,2]. Importantly, the apple peel exhibits a potent antioxidant activity and can greatly inhibit the growth of liver and colon cancer cells [3,4], which confirms the popular saying that an apple a day keeps the doctor away. However, apples and apple trees are vulnerable to pests and diseases, with a noteworthy example being Tetranychus urticae, or red spider, which inflicts serious damage to apple quality. To mitigate this problem, a large number of acaricides are used for insect and disease control, which

(2)

Molecules 2018, 23, 1060 2 of 13

is exemplified by cyflumetofen [2-methoxyethyl-(RS)-2-(4-tert-butylphenyl)-2-cyano-3-oxo-3-(α,α,α-trifluoro-o-tolyl)propionate]. This is a novel acaricide developed by Otsuka AgriTechno Co., Ltd. (Osaka, Japan) that is widely used in orchards for mite control [5]. However, the heavy use of pesticides in orchards has led to many problems, with pesticide contamination becoming one of the most important food safety issues.

Commercial cyflumetofen is a racemic mixture of two enantiomers (see Figure1) that was first registered in Japan in 2007 and is currently approved in 15 countries including China as an agent controlling the growth and reproduction of red spiders by inhibiting the mitochondria complex II [5,6]. The two enantiomers of cyflumetofen exhibit significant differences in toxicity, environmental fate, and bioactivity due to their different interactions with enzymes and other chiral biomolecules [7,8]. The toxicities of cyflumetofen to target mites and human cells are comparable, which deceases in the order of (−)-cyflumetofen > rac-cyflumetofen > (+)-cyflumetofen [9]. This means that the corresponding residues on apples pose a threat to human health [10]. In view of the above and the growing attention attracted by food security issues [11,12], including food contamination with pesticides [13], the investigation of cyflumetofen behavior in apples is a matter of high scientific significance.

Molecules 2018, 23, x FOR PEER REVIEW 2 of 13

quality. To mitigate this problem, a large number of acaricides are used for insect and disease control, which is exemplified by cyflumetofen [2-methoxyethyl-(RS)-2-(4-tert-butylphenyl)-2- cyano-3-oxo-3-(α,α,α-trifluoro-o-tolyl)propionate]. This is a novel acaricide developed by Otsuka AgriTechno Co., Ltd. (Osaka, Japan) that is widely used in orchards for mite control [5]. However, the heavy use of pesticides in orchards has led to many problems, with pesticide contamination becoming one of the most important food safety issues.

Commercial cyflumetofen is a racemic mixture of two enantiomers (see Figure 1) that was first registered in Japan in 2007 and is currently approved in 15 countries including China as an agent controlling the growth and reproduction of red spiders by inhibiting the mitochondria complex II [5,6]. The two enantiomers of cyflumetofen exhibit significant differences in toxicity, environmental fate, and bioactivity due to their different interactions with enzymes and other chiral biomolecules [7,8]. The toxicities of cyflumetofen to target mites and human cells are comparable, which deceases in the order of (−)-cyflumetofen > rac-cyflumetofen > (+)-cyflumetofen [9]. This means that the corresponding residues on apples pose a threat to human health [10]. In view of the above and the growing attention attracted by food security issues [11,12], including food contamination with pesticides [13], the investigation of cyflumetofen behavior in apples is a matter of high scientific significance.

Figure 1. UPCC-MS/MS chromatograms of cyflumetofen enantiomers.

Up to now, research on cyflumetofen enantiomers was mainly focused on developing methods for their separation and individual toxicity determination, such as those based on high-performance liquid chromatography [9] and ultra-performance convergence chromatography coupled with triple quadrupole mass spectrometry [14]. Since the concept of “green chemistry” has become more widely accepted [15,16], ultra-performance convergence chromatography coupled with triple quadrupole mass spectrometry (UPC2-MS/MS) has become an alternative and complementary

method to the HPLC-MS/MS technique [17]. UPC2 integrates supercritical fluid chromatography

(SFC) and ultra-high performance liquid chromatography (UHPLC) technologies [18]. As such SFC is a chromatographic technique in which a supercritical fluid such as supercritical CO2 is used as

the mobile phase, with the advantages of low viscosity, high separation efficiency, environmental benefits [17]. UPC2 offers attractive features, including reduced run times, lower solvent

consumption, and dramatically increased peak capacity and sensitivity [18]. Recently, several studies on the application of UPC2-MS/MS in separating and quantifying basic compounds [19],

isomers [20], and bioactive compounds [21] have been reported.

Figure 1.UPCC-MS/MS chromatograms of cyflumetofen enantiomers.

Up to now, research on cyflumetofen enantiomers was mainly focused on developing methods for their separation and individual toxicity determination, such as those based on high-performance liquid chromatography [9] and ultra-performance convergence chromatography coupled with triple quadrupole mass spectrometry [14]. Since the concept of “green chemistry” has become more widely accepted [15,16], ultra-performance convergence chromatography coupled with triple quadrupole mass spectrometry (UPC2-MS/MS) has become an alternative and complementary method to the HPLC-MS/MS technique [17]. UPC2 integrates supercritical fluid chromatography (SFC) and ultra-high performance liquid chromatography (UHPLC) technologies [18]. As such SFC is a chromatographic technique in which a supercritical fluid such as supercritical CO2is used as the mobile phase, with the advantages of low viscosity, high separation efficiency, environmental benefits [17]. UPC2 offers attractive features, including reduced run times, lower solvent consumption, and dramatically increased peak capacity and sensitivity [18]. Recently, several studies on the application of UPC2-MS/MS in separating and quantifying basic compounds [19], isomers [20], and bioactive compounds [21] have been reported.

(3)

The mechanism of enantioselective cyflumetofen toxicity has already been characterized [6,22–25], e.g., cyflumetofen was shown to induce apoptosis, damage, and G1-phase cycle arrest in SH-SY5Y cells [26]. Hu et al. studied the dynamics of cyflumetofen residues in strawberries and performed the corresponding safety evaluation, which reveal that the highest residue content was observed for cyflumetofen suspension concentrate treatment (0.5882 mg/kg, half-life = 9.364 day) [27]. Liu, et al. studied the distribution of racemic cyflumetofen in home-canned tomatoes, which shows that the processing factor (PF) of tomato samples after each unit process was generally less than unity, whole especially that after the peeling process. This equalled 0.28 [28]. However, the environmental behavior of individual cyflumetofen enantiomers is only scarcely described [9], with the prevalence of studies dealing with racemic cyflumetofen, which poses a risk of inaccurately evaluating the threat posed by cyflumetofen residues to the environment and human beings [28]. Therefore, more research should be conducted to investigate the degradation of cyflumetofen enantiomers for a comprehensive risk assessment.

Cyflumetofen was used as a novel chiral acaricide on the apple. However, some surveys were conducted to determine the occurrence of cyflumetofen in different food products [29,30], especially in citrus, Yet, a few studies attempted to assess its potential risks to human health [31]. In addition, dietary risk assessment associated with cyflumetofen contamination in apple has never been reported previously in China, to our best knowledge. For food quality and safety, the higher residue levels of pesticides in food could not indicate the higher potential health risk of apples intake, because dietary exposure risks relate not only to the pesticide residue levels but also to the pesticide toxicity and food consumption data [32]. Therefore, determination of cyflumetofen in apple is urgently needed for assessing its food safety risks.

Most of the previous studies ignored the special properties of chiral pesticides and the potential safety risks caused by the chiral enantiomers. It has been estimated that 25% of pesticides currently sold are chiral, and the proportion is estimated to be over 40% in China with increasing complex compounds registered for use [33]. In this study, due to the different toxicities of cyflumetofen enantiomers, we aimed to study the enantioselective degradation of cyflumetofen in apples under field conditions and evaluate the distribution pattern of this pesticide, which sheds light on its safe usage and accurate risk evaluation. The result from this study may provide more accurate information for evaluating the apple safety induced by cyflumetofen.

2. Results and Discussion

2.1. Method Validation

Apple samples planted in control plots were used as field blanks. Working solution mixtures of cyflumetofen were added to blank samples at three concentration levels (50 µg/kg, 500 µg/kg, and 1000 µg/kg), which were used for the method recovery assay and detection limit evaluation. The blanks were treated in the same way as other samples throughout the whole analysis.

2.1.1. UPC2System Performance

To obtain good resolution within a reasonable analysis time, Trefoil AMY1 (150 mm×2.1 mm i.d., 2.5 µm particle size; Waters, MA, USA) was used as a chiral chromatographic column, and separation was performed for five minutes using isocratic elution with solvents A (CO2) and B (isopropanol) at a ratio of 96.5:3.5 (v/v) and a flow rate of 1.2 mL/min. As shown in Figure1, good resolution and peak shapes were obtained for the peaks corresponding to the two enantiomers. Subsequently, to improve the separation of the two enantiomers, isopropanol was selected to combine with liquid CO2. These co-solvents were selected as “greener” based on their significantly lower toxicity and limited threat to the natural environment [34,35].

(4)

Molecules 2018, 23, 1060 4 of 13

2.1.2. Linearity, Limit of Detection (LOD), and Limit of Quantitation (LOQ)

Method linearity was determined by linear regression analysis of both standard solution and matrix-matched calibration curves, with the utilized cyflumetofen concentrations equal to 10–5000 µg/L. Satisfactory linearity was observed in all cases (R2> 0.9990).

LOD was defined as the lowest detectable concentration with a signal-to-noise ratio of three, which is equal to 2.8–4.7 µg/L for both (−)- and (+)-cyflumetofen in all apple parts. According to the SANTE/11813/2017 [36] guideline of the European Commission, the LOQ is defined as the lowest spiked level used for method validation, which equalled 10 µg/L in this study.

2.1.3. Matrix Effect, Precision, and Accuracy

The developed method was validated by determining cyflumetofen recoveries and relative standard deviations (RSDs). Since matrix components can affect the ionisation of target compounds, the matrix effect on MS/MS (MRM mode) detection was determined by comparing the standards in working and matrix-matched solutions. As shown in Figure2, the recoveries observed at three concentration levels (50 µg/kg, 500 µg/kg, and 1000 µg/kg) equalled 83.6–118.9% based on acceptable RSDs of 1.1%–14.0%, which falls within the expected range. The values reported in Figure2are “means±standard error of mean”.

Molecules 2018, 23, x FOR PEER REVIEW 4 of 13

2.1.2. Linearity, Limit of Detection (LOD), and Limit of Quantitation (LOQ)

Method linearity was determined by linear regression analysis of both standard solution and matrix-matched calibration curves, with the utilized cyflumetofen concentrations equal to 10–5000 μg/L. Satisfactory linearity was observed in all cases (R2 > 0.9990).

LOD was defined as the lowest detectable concentration with a signal-to-noise ratio of three, which is equal to 2.8–4.7 µ g/L for both (−)- and (+)-cyflumetofen in all apple parts. According to the SANTE/11813/2017 [36] guideline of the European Commission, the LOQ is defined as the lowest spiked level used for method validation, which equalled 10 µ g/L in this study.

2.1.3. Matrix Effect, Precision, and Accuracy

The developed method was validated by determining cyflumetofen recoveries and relative standard deviations (RSDs). Since matrix components can affect the ionisation of target compounds, the matrix effect on MS/MS (MRM mode) detection was determined by comparing the standards in working and matrix-matched solutions. As shown in Figure 2, the recoveries observed at three concentration levels (50 μg/kg, 500 μg/kg, and 1000 μg/kg) equalled 83.6–118.9% based on acceptable RSDs of 1.1%–14.0%, which falls within the expected range. The values reported in Figure 2 are “means ± standard error of mean”.

Figure 2. Cyflumetofen recoveries in seven studied matrices at three spiking levels.

2.1.4. Uncertainty

Uncertainty is a basic characteristic of any measurement, and helps to assure the reliability of an analyst’s work [37]. In this study, the measurement uncertainty was determined for all compounds at three spiked levels using the bottom-up approach based on the in-house validation data in accordance with EURACHEM/CITAC [38]. The main sources of uncertainty were identified and quantified, and the combined uncertainty (Uc) was calculated using the equation below:

Uc = (U12 + U22 + U32 + U42)1/2

where, U1 is the relative standard uncertainty of standards and stock solutions, U2 is the relative

standard uncertainty of the calibration step, U3 is the relative standard uncertainty of repeatability,

and U4 is the relative standard uncertainty of accuracy. The expanded uncertainty (Uexp) was

obtained from the combined uncertainty by multiplying by a coverage factor k = 2 to ensure a level of confidence of 95%, which is shown in the equation below

Uexp = k × Uc

The results obtained for each individual source of uncertainty, the combined uncertainty Uc,

and the expanded uncertainty Uexp are summarized in Table 1. The Uexp values were 6.0% and 8.5%

for (−)-cyflumetofen and (+)-cyflumetofen, respectively, which yielded an average value of 7.3%.

Figure 2.Cyflumetofen recoveries in seven studied matrices at three spiking levels. 2.1.4. Uncertainty

Uncertainty is a basic characteristic of any measurement, and helps to assure the reliability of an analyst’s work [37]. In this study, the measurement uncertainty was determined for all compounds at three spiked levels using the bottom-up approach based on the in-house validation data in accordance with EURACHEM/CITAC [38]. The main sources of uncertainty were identified and quantified, and the combined uncertainty (Uc) was calculated using the equation below:

Uc= (U12+ U22+ U32+ U42)1/2

where, U1is the relative standard uncertainty of standards and stock solutions, U2is the relative standard uncertainty of the calibration step, U3is the relative standard uncertainty of repeatability, and U4is the relative standard uncertainty of accuracy. The expanded uncertainty (Uexp) was obtained from the combined uncertainty by multiplying by a coverage factor k = 2 to ensure a level of confidence of 95%, which is shown in the equation below

(5)

The results obtained for each individual source of uncertainty, the combined uncertainty Uc, and the expanded uncertainty Uexp are summarized in Table1. The Uexp values were 6.0% and 8.5% for (−)-cyflumetofen and (+)-cyflumetofen, respectively, which yielded an average value of 7.3%. This uncertainty is distinctly less than the maximum threshold value of 50% recommended by SANTE/11813/2017 [36], which clearly demonstrates the fitness for the developed method.

Table 1.Uncertainty (Uc) and expanded uncertainty (Uexp) in apple matrices for (−)-cyflumetofen and (+)-cyflumetofen at 50, 500, and 1000 µg/kg.

Uncertainty ()-cyflumetofen (+)-cyflumetofen

U1 0.0025 0.0025 U2 0.0202 0.0305 U3 0.0045 0.0038 U4 0.0218 0.0293 Uc 0.0301 0.0425 Uexp(%) 6.0 8.5

2.2. Stereoselective Degradation of Cyflumetofen

Apple trees were sprayed with 1.5-fold and 5-fold of highest dosage recommended of cyflumetofen SC by the manufacturer under field conditions. The degradation of cyflumetofen enantiomers in apples were demonstrated to follow the pseudo-first-order kinetic model. As shown in Figure3A,B, the concentrations of cyflumetofen stereoisomers were maximal after 2 h and the concentration of (−)-cyflumetofen and (+)-cyflumetofen were achieved as 471.88 µg/kg and 482.50 µg/kg with 1.5-fold applied dosage and 1339.48 µg/kg and 1338.53 µg/kg with 5-fold applied dosage. It was then decreased to almost 50% of the initial values after 10 days. Under the 1.5-fold applied dosage condition, the concentrations of (+)-cyflumetofen enantiomer increased again to 232.40 µg/kg at 14 days. This phenomenon was also observed by Sun et al. [9] in which the two enantiomers of cyflumetofen were increased at 7 days. After 14 days, (−)-cyflumetofen and (+)-cyflumetofen under 1.5-fold applied dosage then gradually declined over time to 168.56 µg/kg and 178.82 µg/kg at 45 days with degradation rates of 63.8% and 62.5%, respectively (see Figure3A). Under 5-fold applied dosages, the two enantiomers gradually declined with time to 520.44 µg/kg and 522.99 µg/kg at 45 days with degradation rates of 61.2% and 60.1%, respectively (see Figure3B).

Molecules 2018, 23, x FOR PEER REVIEW 5 of 13

This uncertainty is distinctly less than the maximum threshold value of 50% recommended by SANTE/11813/2017 [36], which clearly demonstrates the fitness for the developed method.

Table 1. Uncertainty (Uc) and expanded uncertainty (Uexp) in apple matrices for (−)-cyflumetofen and (+)-cyflumetofen at 50, 500, and 1000 μg/kg.

Uncertainty (−)-cyflumetofen (+)-cyflumetofen U1 0.0025 0.0025 U2 0.0202 0.0305 U3 0.0045 0.0038 U4 0.0218 0.0293 Uc 0.0301 0.0425 Uexp (%) 6.0 8.5

2.2. Stereoselective Degradation of Cyflumetofen

Apple trees were sprayed with 1.5-fold and 5-fold of highest dosage recommended of cyflumetofen SC by the manufacturer under field conditions. The degradation of cyflumetofen enantiomers in apples were demonstrated to follow the pseudo-first-order kinetic model. As shown in Figure 3A,B, the concentrations of cyflumetofen stereoisomers were maximal after 2 h and the concentration of (−)-cyflumetofen and (+)-cyflumetofen were achieved as 471.88 μg/kg and 482.50 μg/kg with 1.5-fold applied dosage and 1339.48 μg/kg and 1338.53 μg/kg with 5-fold applied dosage. It was then decreased to almost 50% of the initial values after 10 days. Under the 1.5-fold applied dosage condition, the concentrations of (+)-cyflumetofen enantiomer increased again to 232.40 μg/kg at 14 days. This phenomenon was also observed by Sun et al. [9] in which the two enantiomers of cyflumetofen were increased at 7 days. After 14 days, (−)-cyflumetofen and (+)-cyflumetofen under 1.5-fold applied dosage then gradually declined over time to 168.56 μg/kg and 178.82 μg/kg at 45 days with degradation rates of 63.8% and 62.5%, respectively (see Figure 3A). Under 5-fold applied dosages, the two enantiomers gradually declined with time to 520.44 μg/kg and 522.99 μg/kg at 45 days with degradation rates of 61.2% and 60.1%, respectively (see Figure 3B).

Figure 3. Degradation of cyflumetofen under field conditions, (A) 1.5-fold applied dosage; (B) 5-fold applied dosage; (C) EF value.

T1/2, a crucial indicator of pesticide efficacy and pollution [29,39], was calculated using Equation

(2) (see Table 2), with the values for 5-fold applied dosage (+)-cyflumetofen and (−)-cyflumetofen equal to 22.23 days and 22.13 days, respectively. For 1.5-fold applied dosage, the respective values were determined as 23.64 days and 22.42 days, which indicates that dilution did not exhibit a significant effect on the cyflumetofen half-life. In addition, half-lives of cyflumetofen in apples were longer than in citrus and strawberries which was reported to be 19.77 day and 9.36 day, respectively [9,27].

Figure 3.Degradation of cyflumetofen under field conditions, (A) 1.5-fold applied dosage; (B) 5-fold applied dosage; (C) EF value.

T1/2, a crucial indicator of pesticide efficacy and pollution [29,39], was calculated using Equation (2) (see Table2), with the values for 5-fold applied dosage (+)-cyflumetofen and (−)-cyflumetofen equal to 22.23 days and 22.13 days, respectively. For 1.5-fold applied dosage, the respective values were determined as 23.64 days and 22.42 days, which indicates that dilution did not exhibit a significant effect on the cyflumetofen half-life. In addition, half-lives of cyflumetofen in apples were longer than in citrus and strawberries which was reported to be 19.77 days and 9.36 days, respectively [9,27].

(6)

Molecules 2018, 23, 1060 6 of 13

Table 2. Degradation kinetic constant (k), Half-life (T1/2) and correlation coefficient (R2) values of cyflumetofen in apple.

Sample Enantiomer K×10−2(day−1) T1/2(day) R2

Apple (1.5-fold dosage) (−)-cyflumetofen 4.01 22.42a 0.7938 (+)-cyflumetofen 3.32 23.64a 0.7662 Apple (5-fold dosage) (−)-cyflumetofen 3.17 22.13a 0.7468 (+)-cyflumetofen 2.70 22.23a 0.7736

EF is a straightforward measure of enantioselectivity since it is defined by Equation (3) [40]. Notably, cyflumetofen EF values during the field trial were maintained at ~0.50 (see Figure3C), which indicates that both enantiomers exhibit very similar degradation behaviors. Eventual experiments showed that the degradation of (−)-cyflumetofen was slightly faster than that of (+)-cyflumetofen, with the corresponding enantioselectivity being very weakly pronounced, which was ascribed to the absence of a chiral degradation environment.

Microbial action is known to play an important role in the degradation of malathion, which is a widely used chiral pesticide [41]. In this regard, the investigation of the field-to-table fate of cyflumetofen residues in apples appeared meaningful, which led us to study the fate of cyflumetofen enantiomers during apple processing, especially in the course of fermentation.

2.3. Distribution of Cyflumetofen in Apples

Figure4A,B reveals that both cyflumetofen enantiomers featured very similar distributions in apples since they are predominantly concentrated in the apple peel (50% of the total cyflumetofen content). The implies and implying that apples should be peeled prior to consumption. The obtained results were supported by Liu [28], who estimated the PF of the peeling process for cyflumetofen as 0.28. Han et al. showed that peeling and coring lead to the loss of 62.9% of spirotetramat-enol and 76.4% of spirotetramat from apples, with the PFs of coring and peeling estimated as 0.22 and 0.14, respectively [42]. Moreover, 22% of cyflumetofen was contained in the apple peduncle (a sag area easily accumulating pesticides), which highlights the importance of removing this part before apple consumption. In addition, the apple pomace also accounted for a considerable cyflumetofen fraction due to the poor water solubility of this pesticide. Therefore, safety issues need to be taken into account when apple pomace and apple peel are used for the extraction of polyphenols and flavonoids.

Molecules 2018, 23, x FOR PEER REVIEW 6 of 13

Table 2. Degradation kinetic constant (k), Half-life (T1/2) and correlation coefficient (R2) values of cyflumetofen in apple.

Sample Enantiomer K × 10−2 (day−1) T1/2 (day) R2 Apple (1.5-fold dosage) (−)-cyflumetofen 4.01 22.42a 0.7938 (+)-cyflumetofen 3.32 23.64a 0.7662 Apple (5-fold dosage) (−)-cyflumetofen 3.17 22.13a 0.7468 (+)-cyflumetofen 2.70 22.23a 0.7736

EF is a straightforward measure of enantioselectivity since it is defined by Equation (3) [40]. Notably, cyflumetofen EF values during the field trial were maintained at ~0.50 (see Figure 3C), which indicates that both enantiomers exhibit very similar degradation behaviors. Eventual experiments showed that the degradation of (−)-cyflumetofen was slightly faster than that of (+)-cyflumetofen, with the corresponding enantioselectivity being very weakly pronounced, which was ascribed to the absence of a chiral degradation environment.

Microbial action is known to play an important role in the degradation of malathion, which is a widely used chiral pesticide [41]. In this regard, the investigation of the field-to-table fate of cyflumetofen residues in apples appeared meaningful, which led us to study the fate of cyflumetofen enantiomers during apple processing, especially in the course of fermentation.

2.3. Distribution of Cyflumetofen in Apples

Figure 4A,B reveals that both cyflumetofen enantiomers featured very similar distributions in apples since they are predominantly concentrated in the apple peel (50% of the total cyflumetofen content). The implies and implying that apples should be peeled prior to consumption. The obtained results were supported by Liu [28], who estimated the PF of the peeling process for cyflumetofen as 0.28. Han et al. showed that peeling and coring lead to the loss of 62.9% of spirotetramat-enol and 76.4% of spirotetramat from apples, with the PFs of coring and peeling estimated as 0.22 and 0.14, respectively [42]. Moreover, 22% of cyflumetofen was contained in the apple peduncle (a sag area easily accumulating pesticides), which highlights the importance of removing this part before apple consumption. In addition, the apple pomace also accounted for a considerable cyflumetofen fraction due to the poor water solubility of this pesticide. Therefore, safety issues need to be taken into account when apple pomace and apple peel are used for the extraction of polyphenols and flavonoids.

Figure 4. Distributions of cyflumetofen in apple samples, (A) (−)-cyflumetofen; (B) (+)-cyflumetofen.

2.4. Dietary Intake Risk Assessment

The acceptable daily intake (ADI) of cyflumetofen per kg of body weight was determined to be 0.17 mg/kg bw/day on the European Food Safety Authority [43]. The STMRi in 1.5-fold dosage and 5-fold dosage apples is 0.22 mg/kg and 1.04 mg/kg, respectively. Characterizations of the population and apple consumption data were obtained from the 2002 Chinese National Nutrition and Health Survey (CNNHS) conducted via the 24-h recall method using a multistage and random cluster

Figure 4.Distributions of cyflumetofen in apple samples, (A) ()-cyflumetofen; (B) (+)-cyflumetofen.

2.4. Dietary Intake Risk Assessment

The acceptable daily intake (ADI) of cyflumetofen per kg of body weight was determined to be 0.17 mg/kg bw/day on the European Food Safety Authority [43]. The STMRi in 1.5-fold dosage and 5-fold dosage apples is 0.22 mg/kg and 1.04 mg/kg, respectively. Characterizations of the population

(7)

and apple consumption data were obtained from the 2002 Chinese National Nutrition and Health Survey (CNNHS) conducted via the 24-h recall method using a multistage and random cluster process. The average apple consumption in different subgroups was calculated by taking into consideration detailed information on total production, export, processing, and storage loss of apples in China [44]. The equivalent calculation was performed according to the proportion relationship of the consumption of fruits for different subgroups in the 2002 survey. Table3lists average body weights and apple consumption data in different age groups.

Table 3.Characterization of the population and dietary intake of apples.

Subpopulation Age

Average Body Weight (kg) Consumption of Apples (g·day−1)

Female Male Female Male

Urban Rural Urban Rural Urban Rural Urban Rural

Kids 2–6 17.4 15.5 18.3 16.1 126.3 109.5 134.1 99.4

Children 7–13 34.1 29.4 35.3 29.6 154.9 96.6 147.0 101.4

Teenagers 14–17 51.0 47.8 56.2 50.4 209.0 108.3 177.1 91.5

Adults 18–59 56.0 54.0 65.7 60.5 162.2 84.0 118.3 73.6

Seniors ≥60 54.9 48.8 63.7 55.9 132.8 42.3 142.6 45.9

Table4lists the dietary intake risk assessment results of cyflumetofen for different age groups in urban and rural areas. Generally, kids were considered the most vulnerable group because they were particularly susceptible to the hazards associated with pesticides and tended to eat more apples on a body-weight basis [45–47]. From Table4, we found that most of RQ % was more than 1 under 5-fold applied dosage, and this was because higher levels of applied pesticide dosage have more pesticide residue in the food. In addition, under 1.5-fold condition, we found higher health risks for kids compared with other age groups because the RQ % were 0.8 with rural male and more than 0.9 in urban male, rural female and urban female. This could be due to the consumption of fruits (including apple) in rural male of children, which were less than other children. Furthermore, exposure risks faced by teenagers, young adults, and seniors appeared to decline successively. In sum, the consumption of apples with residue of cyflumetofen did not pose a health risk to the population if the farmer applied the cyflumetofen under good agricultural practices.

Table 4.Dietary intake risk assessment of cyflumetofen in whole apple.

Subpopulation Age

RQ %

1.5-Fold 5-Fold

Female Male Female Male

Urban Rural Urban Rural Urban Rural Urban Rural

Kids 2–6 0.94 0.91 0.95 0.80 4.44 4.32 4.48 3.78

Children 7–13 0.59 0.43 0.54 0.44 2.78 2.01 2.55 2.10

Teenagers 14–17 0.53 0.29 0.41 0.23 2.51 1.39 1.93 1.11

Adults 18–59 0.37 0.20 0.23 0.16 1.77 0.95 1.10 0.74

Seniors ≥60 0.31 0.11 0.29 0.11 1.48 0.53 1.37 0.50

3. Materials and Methods

3.1. Chemicals and Reagents

Analytical-grade cyflumetofen (97%) was purchased from Otsuka AgriTechno Co., Ltd. (Osaka, Japan), and commercial 20% cyflumetofen suspension concentrate (SC) was obtained from Jiangsu FMC Corporation (Jiangsu, China). Ultra-pure water was obtained using a Milli-Q system (Millipore, Burlington, MA, USA). HPLC-grade isopropanol, methanol, and acetonitrile were purchased from

(8)

Molecules 2018, 23, 1060 8 of 13

Fisher Scientific (Shanghai, China), which was in the form of formic acid (FA). Analytical-grade anhydrous MgSO4and NaCl were purchased from Sinopharm Chemical Reagent Co., Ltd. Graphitised carbon black, primary secondary amine (PSA), and C18were purchased from DIKMA (Beijing, China). Samples were filtered through a 0.22-µm organic filter membrane (Shanghai, China) before injection.

Standard cyflumetofen stock solutions (1000 mg/L) were prepared in pure acetonitrile, and standard working solutions (0.01 mg/L, 0.05 mg/L, 0.1 mg/L, 0.5 mg/L, 1.0 mg/L, 3.0 mg/L, and 5.0 mg/L) for calibration curve construction were prepared in pure acetonitrile by serial dilution of the stock solution. Matrix-matched standard solutions were prepared at concentrations of 0.01 mg/L, 0.05 mg/L, 0.1 mg/L, 0.5 mg/L, 1.0 mg/L, 3.0 mg/L, and 5.0 mg/L by adding blank apple, apple juice, and apple cider extracts to each serially diluted standard solution. All sample and standard solutions were protected from light with aluminium foil and stored in a refrigerator at 4◦C until analysis. The working standard solutions underwent no degradation during a three-month storage.

3.2. Field Trials

Field experiments were performed at an experimental base (Beijing) from July to October 2016, with the experimental field surveyed and determined to be cyflumetofen-free before these experiments. Commercial 20% cyflumetofen SC was applied at the 1.5-fold and 5-fold of highest dosage recommended by the manufacturer of 0.20 and 0.67 active ingredient mg/kg to ensure sufficient pesticide primary deposit for the following degradation and processing studies. Target apples were sprayed to achieve an even distribution on the front and back sides of apple leaves, the fruit surface, trunk, and branches. Spraying was performed until the cyflumetofen suspension concentrate started to form droplets and drop down from the fruit surface. Two sprayings were performed using the above method. The interval between two applications was 10 days. Three kilograms of apple samples were picked at 0 (2 h), 1 day, 3 days, 5 days, 7 days, 10 days, 14 days, 21 days, and 28 days after the last spraying, and all the remaining apple samples were picked at 45 days after the last spraying. Then these apple samples were put into polyethylene bags, and transported to the laboratory, where some of these samples were used for studying cyflumetofen distributions. The other ones were chopped, mixed, divided into subsamples, and stored at−20◦C until analysis.

3.3. Distribution of Cyflumetofen in Apples

Apples were hand-peeled using a peeler, with the thickness of the removed skin equal to 0.2 cm [10]. The apple core, pedicel and peduncle were cut into pieces, and the remaining fruit was cored, peeled, cut into quarters, and put into an automatic juice extractor to produce juice and pomace.

3.4. Extraction and Purification

Figure5showed the extraction and purification steps of the analytical procedure. 10.0 g of homogenised samples were weighed into a 50-mL polypropylene centrifuge tube, and then charged with water (5 mL) and acetonitrile (10 mL) and mechanically shaken (SPEX Sample Prep, Metuchen, NJ, USA) for 5 min at 1200 strokes per minute. Next, anhydrous MgSO4(4.0 g) and NaCl (1.0 g) were added to the mixture, which was followed by 3-min full-speed vortexing (XW-80A Vortex, Kirin Medical Instrument, Jiaxing, China) and 5 min centrifugation at 5000 rpm/min (TG16-WS, Xiangyi Centrifuge Machines, Changsha, China). Subsequently, 1.5 mL of the obtained supernatant was transferred to a 2-mL polypropylene centrifuge tube containing cleaning sorbent. In addition, the tube was vortexed at full speed for 2 min and centrifuged for 5 min, with 1 mL of the upper layer subsequently filtered through a 0.22 µm organic nylon membrane for UPC2-MS/MS analysis [23,29].

3.5. Chromatographic and Mass Spectrometric Conditions

An Acquity UPC2system (Waters, Milford, MA, USA) equipped with a column manager, binary solvent manager, sample manager-FL, convergence manager, and a Waters 515 compensation pump was used for detection. Trefoil AMY1 (150 mm×2.1 mm i.d., 2.5 µm particle size; Waters, Milford,

(9)

MA, USA) was used as a chiral chromatographic column. Separation was performed for 5 min using isocratic elution with solvents A (CO2) and B (isopropanol) at a ratio of 96.5:3.5 (v/v) and a flow rate of 1.2 mL/min. The automated backpressure regulator pressure (ABPR) was set at 2000 psi, and 0.1% FA/MeOH (v/v) was employed as a post-column additive of the 515 compensation pump at a flow rate of 0.40 mL/min. The sample manager and column were maintained at 25◦C and 40◦C, respectively, and the sample injection volume was set at 1 µL [14].

Molecules 2018, 23, x FOR PEER REVIEW 9 of 13

compensation pump at a flow rate of 0.40 mL/min. The sample manager and column were maintained at 25 °C and 40 °C, respectively, and the sample injection volume was set at 1 μL [14].

Figure 5. Diagram of analytical procedure including extraction and purification steps.

Detection of cyflumetofen stereoisomers was performed by using a triple quadrupole Xevo-TQD mass spectrometer (Waters, Milford, MA, USA) operated in positive-ion ESI mode. The following acquisition parameters were utilized: source temperature = 150 °C, desolvation temperature = 500 °C, and capillary voltage = 3.5 kV. The gas consisted of collision gas (99.99% Ar) and nebuliser gas (99.95% N2) at a pressure of 2 × 10−3 mbar in a T-wave cell. Cone and desolvation

gas flows equalled 50 L/h and 900 L/h, respectively. Species with m/z 448 and 173 were selected as cyflumetofen precursor and quantitative product ions, respectively. Multiple reaction monitoring (MRM) was selected as the scan mode [14].

3.6. Dissipation Kinetics and Enantioselectivity of Cyflumetofen

All experiments were repeated three times, and values were reported as the mean ± standard deviation. Analysis of variance was utilized to compare data between groups, with p values below 0.05 (t-test) considered statistically significant. All statistical analyses were performed in SAS (version 9.2, SAS Institute, Beijing, China). The half-life T1/2 (d) in apples was calculated according to

the equations below.

C = C0e−kt (1)

T1/2 = ln2/k (2)

where, C is the residue concentration (mg/kg) of cyflumetofen at time point t (day), C0 is the initial

concentration (mg/kg) of the pesticide, and k is the cyflumetofen degradation rate constant (day−1).

Enantiomer fractions (EFs, ranging from 0 to 1 and equal to 0.5 for a racemic mixture) were used to evaluate the enantioselectivity of cyflumetofen degradation in apple samples. This was determined using the equation below.

EF = Concentration of (−) − cyflumetofen

Sum of (−) − and (+) − cyflumetofen concentrations (3)

3.7. Dietary Intake Risk Assessment

The long-term dietary risk assessment of cyflumetofen in apple was calculated by using Equations (4) and (5).

Figure 5.Diagram of analytical procedure including extraction and purification steps.

Detection of cyflumetofen stereoisomers was performed by using a triple quadrupole Xevo-TQD mass spectrometer (Waters, Milford, MA, USA) operated in positive-ion ESI mode. The following acquisition parameters were utilized: source temperature = 150◦C, desolvation temperature = 500◦C, and capillary voltage = 3.5 kV. The gas consisted of collision gas (99.99% Ar) and nebuliser gas (99.95% N2) at a pressure of 2×10−3mbar in a T-wave cell. Cone and desolvation gas flows equalled 50 L/h and 900 L/h, respectively. Species with m/z 448 and 173 were selected as cyflumetofen precursor and quantitative product ions, respectively. Multiple reaction monitoring (MRM) was selected as the scan mode [14].

3.6. Dissipation Kinetics and Enantioselectivity of Cyflumetofen

All experiments were repeated three times, and values were reported as the mean±standard deviation. Analysis of variance was utilized to compare data between groups, with p values below 0.05 (t-test) considered statistically significant. All statistical analyses were performed in SAS (version 9.2, SAS Institute, Beijing, China). The half-life T1/2 (d) in apples was calculated according to the equations below.

C = C0e−kt (1)

T1/2= ln2/k (2)

where, C is the residue concentration (mg/kg) of cyflumetofen at time point t (day), C0is the initial concentration (mg/kg) of the pesticide, and k is the cyflumetofen degradation rate constant (day−1).

Enantiomer fractions (EFs, ranging from 0 to 1 and equal to 0.5 for a racemic mixture) were used to evaluate the enantioselectivity of cyflumetofen degradation in apple samples. This was determined using the equation below.

(10)

Molecules 2018, 23, 1060 10 of 13

EF= Concentration of(−) −cyflumetofen

Sum of(−) − and(+) −cyflumetofen concentrations (3) 3.7. Dietary Intake Risk Assessment

The long-term dietary risk assessment of cyflumetofen in apple was calculated by using Equations (4) and (5).

NEDI =

(STMRi×Ei×Pi×Fi) (4)

RQ % = NEDI/(ADI×bw)×100 (5)

where NEDI is Estimated Daily Intake. STMRi is the supervised trials median residue level and the mean value of the final residue was used in this study. Fi is the apple per day consumption (kg/d). RQ is Risk Quotient. Ei and Pi refer to the factor for the edible part and the processing factor of a particular food product, respectively. In this study, the difference was not considered and both Ei and Pi were set to 1. ADI is the acceptable daily intake in mg/kg bw. bw refers to body weight in kg and in general; RQ % > 1 indicates the presence of unacceptable risk while RQ % < 1 indicates an acceptable risk. The risk is positively correlated to the RQ value [48].

4. Conclusions

In this paper, we investigated the distribution and enantioselective degradation of cyflumetofen in apples and, observed almost no differences in the behaviors of the two enantiomers. The degradation rate of (−)-cyflumetofen was only insignificantly faster than that of (+)-cyflumetofen. Importantly, cyflumetofen was concentrated in the apple peel and pomace, which implies that safety considerations need to be taken into account when these parts are used for bioactive molecule extraction. Overall, the current study shed new light on the stereoselective dissipation and distribution of cyflumetofen, which contributes to a better understanding of this novel acaricide and provides more accurate information for comprehensive risk assessment and regulatory decisions related to the use of cyflumetofen in agricultural production. After the long-term dietary risk assessment, the consumption of apples with residue of cyflumetofen did not pose a health risk to the population if the farmer applied the cyflumetofen under satisfactory agricultural practices.

The result of this study showed that there is urgent need to monitor the pesticide residues to standardize the application doses especially for chiral pesticides. Pest management is one of the major inputs in agricultural production the chiral pesticide needs great attention to economize the production, to provide safe foods and to lower the medical expenses for treatment of resulting ailments. As for agricultural use, potential substitution of rac-cyflumetofen with isomer-enriched compound should take into consideration to reduce the residues in plant and reduce the negative effect on environment and human health. In this study, (−)-cyflumetofen was insignificantly faster than that of (+)-cyflumetofen, and Sun et al., [9] found that (+)-cyflumetofen was much lower in cytotoxicity when compared with (−)-cyflumetofen. Therefore, (+)-cyflumetofen might be developed as the substitution of cyflumetofen racemate if it is more efficient to target organisms than (−)-cyflumetofen. In addition, the results would further enable research on health risk characterization from realistic dietary exposures to pesticide residues, which would enable the settlement of MRLs or processing factors for pesticide residues in food products, and further enable the optimization of food technology processes with regard to pesticide residues dissipation. Overall, the findings of this study provide some implications for better understanding of this new pesticide and provide some relevance to the registration and usage advice. In the future, we plan to investigate the fate of cyflumetofen enantiomers during apple processing (focusing on the fermentation) to provide some implications for better environmental and ecological risk assessment.

Author Contributions: J.G. and M.L. carried out the study, the data analysis, and writing. Y.L. carried out literature search and research design. F.W. carried out research design and data analysis. Z.K. carried out research design, data analysis, and writing. Y.S. carried out data analysis. J.L. and N.J. carried out data interpretation. Y.H.

(11)

and J.L. carried out literature search. F.F. carried out research design. B.F. carried out literature search, research design and data analysis.

Acknowledgments:This study was supported by the National Natural Science Foundation of China (31671942 and 31401580). We thank the University of Liège-Gembloux Agro-Bio Tech (MOE11-BE1A20131371N), and more specifically the research platform Agriculture Is Life for the funding of this research project.

Conflicts of Interest:The authors declare no conflict of interest. Abbreviations

The following abbreviations are used in this manuscript.

UPC2-MS/MS Ultra-performance convergence chromatography coupled with triple quadrupole mass spectrometry

PF Processing factor

SC Suspension concentration

PSA Primary secondary amine

MRM Multiple reaction monitoring

EF Enantiomeric fraction

LOD Limit of detection

LOQ Limit of quantitation

ABPR Automated back pressure regulator

FA Formic acid

RSD Relative standard deviations

ADI Acceptable daily intake

NEDI National estimated daily intake STRM Standardized test residue median

RQ Risk quotient

References

1. Pennell, D.; Bradshaw, N.; Ogilvy, S. Food Standards Agency Pesticide Residue Minimisation Crop Guide. 2006. Available online:Multimedia.food.gov.uk(accessed on 1 November 2006).

2. Brown, S. Apple; Springer: Boston, MA, USA, 2012.

3. Eberhardt, M.V.; Chang, Y.L.; Rui, H.L. Nutrition: Antioxidant activity of fresh apples. Nature 2000, 405, 903–904. [CrossRef] [PubMed]

4. Wolfe, K.; Wu, X.; Liu, R.H. Antioxidant Activity of Apple Peels. J. Agric. Food Chem. 2003, 51, 609–614. [CrossRef] [PubMed]

5. Takahashi, N.; Nakagawa, H.; Sasama, Y.; Ikemi, N. Development of a new acaricide, cyflumetofen. J. Pestic. Sci. 2012, 37, 263–264. [CrossRef]

6. Hayashi, N.; Sasama, Y.; Takahashi, N.; Ikemi, N. Cyflumetofen, a novel acaricide—Its mode of action and selectivity. Pest Manag. Sci. 2013, 69, 1080–1084. [CrossRef] [PubMed]

7. Liu, W.; Gan, J.D.; Jury, W.A. Enantioselectivity in environmental safety of current chiral insecticides. Proc. Natl. Acad. Sci. USA 2005, 102, 701–706. [CrossRef] [PubMed]

8. Liu, Y.; Zhang, X.; Liu, C.; Yang, R.; Xu, Z.; Zhou, L.; Sun, Y.; Lei, H. Enantioselective and Synergetic Toxicity of Axial Chiral Herbicide Propisochlor to SP2/0 Myeloma Cells. J. Agric. Food Chem. 2015, 63, 7914–7920. [CrossRef] [PubMed]

9. Sun, D.; Pang, J.; Zhou, Z.; Jiao, B. Enantioselective environmental behavior and cytotoxicity of chiral acaricide cyflumetofen. Chemosphere 2016, 161, 167–173. [CrossRef] [PubMed]

10. Kong, Z.; Shan, W.; Dong, F.; Liu, X.; Xu, J.; Li, M.; Zheng, Y. Effect of home processing on the distribution and reduction of pesticide residues in apples. Food Addit. Contam. Part A 2012, 29, 1280–1287. [CrossRef] [PubMed]

11. Barrett, C.B. Measuring food insecurity. Science 2010, 327, 825–828. [CrossRef] [PubMed]

12. Godfray, H.C.J.; Beddington, J.R.; Crute, I.R.; Haddad, L.; Lawrence, D.; Muir, J.F.; Pretty, J.; Robinson, S.; Thomas, S.M.; Toulmin, C. Food security: The challenge of feeding 9 billion people. Science 2010, 327, 812–818. [CrossRef] [PubMed]

13. Ling, Y.; Wang, H.; Yong, W.; Zhang, F.; Sun, L.; Yang, M.L.; Wu, Y.N.; Chu, X.G. The effects of washing and cooking on chlorpyrifos and its toxic metabolites in vegetables. Food Control 2011, 22, 54–58. [CrossRef]

(12)

Molecules 2018, 23, 1060 12 of 13

14. Liu, N.; Dong, F.; Xu, J.; Liu, X.; Chen, Z.; Pan, X.; Chen, X.; Zheng, Y. Enantioselective separation and pharmacokinetic dissipation of cyflumetofen in field soil by ultra-performance convergence chromatography with tandem mass spectrometry. J. Sep. Sci. 2016, 39, 1363–1370. [CrossRef] [PubMed]

15. Gałuszka, A.; Migaszewski, Z.M.; Konieczka, P.; Namie´snik, J. Analytical Eco-Scale for assessing the greenness of analytical procedures. Trends Anal. Chem. 2012, 37, 61–72. [CrossRef]

16. Płotka-Wasylka, J. A new tool for the evaluation of the analytical procedure: Green Analytical Procedure Index. Talanta 2018, 18, 204–209. [CrossRef] [PubMed]

17. Geng, Y.; Zhao, L.; Zhao, J.; Guo, B.; Ma, P.; Li, Y.; Zhang, T. Development of a supercritical fluid chromatography-tandem mass spectrometry method for the determination of lacidipine in beagle dog plasma and its application to a bioavailability study. J. Chromatogr. B Anal. Technol. Biomed. Life Sci. 2014, 945–946, 121–126. [CrossRef] [PubMed]

18. Gong, X.; Qi, N.; Wang, X.; Lin, L.; Li, J. Ultra-performance convergence chromatography (UPC2) method for the analysis of biogenic amines in fermented foods. Food Chem. 2014, 162, 172–175. [CrossRef] [PubMed] 19. Du, T.T.; Stander, M.A.; Swart, A.C. A high-throughput UPC2-MS/MS method for the separation and

quantification of C19 and C21 steroids and their C11-oxy steroid metabolites in the classical, alternative, backdoor and 11OHA4 steroid pathways. J. Chromatogr. B Anal. Technol. Biomed. Life Sci. 2018, 1080, 71–81. 20. Chen, Z.; Dong, F.; Xu, J.; Liu, X.; Cheng, Y.; Liu, N.; Tao, Y.; Pan, X.; Zheng, Y. Stereoselective separation and pharmacokinetic dissipation of the chiral neonicotinoid sulfoxaflor in soil by ultraperformance convergence chromatography/tandem mass spectrometry. Anal. Bioanal. Chem. 2014, 406, 6677–6690. [CrossRef] [PubMed]

21. Kim, H.S.; Jin, M.C.; Kwon, B.I.; Lee, A.R.; Kim, H.K.; Lee, A.Y. Development and validation of an ultra-performance convergence chromatography method for the quality control of Angelica gigas Nakai. J. Sep. Sci. 2016, 39, 4035–4041. [CrossRef] [PubMed]

22. Marcic, D. Acaricides in modern management of plant-feeding mites. J. Pest Sci. 2012, 85, 395–408. [CrossRef] 23. Ullah, M.S.; Gotoh, T. Laboratory-based toxicity of some acaricides to Tetranychus macfarlanei and

Tetranychus truncatus (Acari: Tetranychidae). Int. J. Acarol. 2013, 39, 244–251. [CrossRef]

24. Wang, Y.; Zhao, S.; Shi, L.; Xu, Z.; He, L. Resistance selection and biochemical mechanism of resistance against cyflumetofen in Tetranychus cinnabarinus (Boisduval). Pestic. Biochem. Physiol. 2014, 111, 24–30. [CrossRef] [PubMed]

25. Van, L.T.; Tirry, L.; Yamamoto, A.; Nauen, R.; Dermauw, W. The economic importance of acaricides in the control of phytophagous mites and an update on recent acaricide mode of action research. Pestic. Biochem. Physiol. 2015, 121, 12–21.

26. Zhao, H.Z.; Chen, Y.X.; Nan, L.I.; Xu, Y.; Sai-Nan, L.I.; Liu, W.H. Cytotoxicity of cyflumetofen on SH-SY5Y cells and possible mechanism. Chin. J. Pharmacol. Toxicol. 2017, 31, 318–324.

27. Xuan-Xiang, H.U.; Shao, M.H.; Hong, W.Y.; Yan-Jun, W.U.; Han-Yun, K.E.; Zhao, S.F.; Bureau, J.A. Residue dynamics and safely applying technology of cyflumetofen in strawberry. Acta Agric. Zhejiangensis 2014, 26, 1558–1563.

28. Liu, N.; Dong, F.; Chen, Z.; Xu, J.; Liu, X.; Duan, L.; Li, M.; Zheng, Y. Distribution behaviour of acaricide cyflumetofen in tomato during home canning. Food Addit. Contam. Part A 2016, 33, 824–830. [CrossRef] [PubMed]

29. Li, Y.; Dong, F.; Liu, X.; Xu, J.; Han, Y.; Zheng, Y. Chiral fungicide triadimefon and triadimenol: Stereoselective transformation in greenhouse crops and soil, and toxicity to Daphnia magna. J. Hazard. Mater. 2014, 265, 115–123. [CrossRef] [PubMed]

30. Li, M.; Liu, X.; Dong, F.; Xu, J.; Kong, Z.; Li, Y.; Zheng, Y. Simultaneous determination of cyflumetofen and its main metabolite residues in samples of plant and animal origin using multi-walled carbon nanotubes in dispersive solid-phase extraction and ultrahigh performance liquid chromatography- tandem mass spectrome. J. Chromatogr. A 2013, 1300, 95–103. [PubMed]

31. Yoshida, T.; Ikemi, N.; Takeuchi, Y.; Ebino, K.; Kojima, S.; Chiba, Y.; Nakashima, N.; Kawakatsu, H.; Saka, M.; Harada, T. A repeated dose 90-day oral toxicity study of cyflumetofen, a novel acaricide, in rats. J. Toxicol. Sci. 2012, 37, 91–104. [CrossRef] [PubMed]

32. Ye, M.; Nie, J.; Li, Z.; Cheng, Y.; Zheng, L.; Xu, G.; Yan, Z. Health risks of consuming apples with carbendazim, imidacloprid, and thiophanate-methyl in the Chinese population: Risk assessment based on a nonparametric probabilistic evaluation model. Hum. Ecol. Risk Assess. Int. J. 2016, 22, 1106–1121. [CrossRef]

(13)

33. Williams, A. Opportunities for chiral chemicals. Pestic. Sci. 1996, 46, 3–9. [CrossRef]

34. Prat, D.; Hayler, J.; Wells, A. A survey of solvent selection guides. Green Chem. 2014, 16, 4546–4551. [CrossRef] 35. Tobiszewski, M.; Tsakovski, S.; Simeonov, V.; Namie´snik, J.; Penapereira, F. Correction: A solvent selection guide based on chemometrics and multicriteria decision analysis. Green Chem. 2015, 17, 4773–4785. [CrossRef]

36. European Commission. Guidance Document on Analytical Quality Control and Validation Procedures for Pesticide Residues Analysis in Food and Feed. SANTE/11813/2017. Available online:https://ec.europa. eu/food/sites/food/files/plant/docs/pesticides_mrl_guidelines_wrkdoc_2017-11813.pdf(accessed on 1 March 2018).

37. Xu, R.; Mao, F.; Zhao, Y.; Wang, W.; Fan, L.; Gao, X.; Zhao, J.; Tian, H. UPLC Quantitative Analysis of Multi-Components by Single Marker and Quality Evaluation of Polygala tenuifolia Wild. Extracts. Molecules 2017, 22. [CrossRef] [PubMed]

38. Ellison, S.L.R.; Rosslein, M.; Williams, A.; Konopel’Ko, L.A.; Garmash, A.V. EURACHEM/CITAC Guide: Quantifying Uncertainty in Analytical Measurement; Eurachem: Olomouc, Czech Republic, 2000.

39. Zhang, H.; Wang, X.; Qian, M.; Wang, X.; Xu, H.; Xu, M.; Wang, Q. Residue analysis and degradation studies of fenbuconazole and myclobutanil in strawberry by chiral high-performance liquid chromatography-tandem mass spectrometry. J. Agric. Food Chem. 2011, 59, 12012–12017. [CrossRef] [PubMed]

40. Chen, Z.; Dong, F.; Pan, X.; Xu, J.; Liu, X.; Wu, X.; Zheng, Y. Influence of Uptake Pathways on the Stereoselective Dissipation of Chiral Neonicotinoid Sulfoxaflor in Greenhouse Vegetables. J. Agric. Food Chem. 2016, 64, 2655–2660. [CrossRef] [PubMed]

41. Sun, M.; Liu, D.; Zhou, G.; Li, J.; Qiu, X.; Zhou, Z.; Wang, P. Enantioselective degradation and chiral stability of malathion in environmental samples. J. Agric. Food Chem. 2012, 60, 372–379. [CrossRef] [PubMed] 42. Han, Y.; Xu, J.; Dong, F.; Li, W.; Liu, X.; Li, Y.; Kong, Z.; Zhu, Y.; Liu, N.; Zheng, Y. The fate of spirotetramat

and its metabolite spirotetramat-enol in apple samples during apple cider processing. Food Control 2013, 34, 283–290. [CrossRef]

43. European Food Safety Authority. Conclusion on the peer review of the pesticide risk assessment of the active substance cyflumetofen. EFSA J. 2006, 10. [CrossRef]

44. Nie, J.Y.; Li, Z.X.; Liu, C.D.; Fang, J.B.; Wang, C.; Guo, Y.Z.; Lei, S.R.; Li, H.F.; Xu, G.F.; Yan, Z. Risk Assessment of Pesticide Residues in Apples. Sci. Agric. Sin. 2014, 47, 3655–3667.

45. Lozowicka, B. Health risk for children and adults consuming apples with pesticide residue. Sci. Total Environ. 2015, 502, 184–198. [CrossRef] [PubMed]

46. He, D.; Ye, X.; Xiao, Y.; Zhao, N.; Long, J.; Zhang, P.; Fan, Y.; Ding, S.; Jin, X.; Tian, C. Dietary exposure to endocrine disrupting chemicals in metropolitan population from China: A risk assessment based on probabilistic approach. Chemosphere 2015, 139, 2–8. [CrossRef] [PubMed]

47. Szpyrka, E.; Walorczyk, S. Dissipation kinetics of fluquinconazole and pyrimethanil residues in apples intended for baby food production. Food Chem. 2013, 141, 3525–3530. [CrossRef] [PubMed]

48. Peterson, R.K. Comparing ecological risks of pesticides: The utility of a Risk Quotient ranking approach across refinements of exposure. Pest Manag. Sci. 2006, 62, 46–56. [CrossRef] [PubMed]

Sample Availability:Samples of the compounds are available from the authors.

© 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

Figure

Figure 1. UPCC-MS/MS chromatograms of cyflumetofen enantiomers.
Figure 2. Cyflumetofen recoveries in seven studied matrices at three spiking levels.
Table  1.  Uncertainty  (U c )  and  expanded  uncertainty  (U exp )  in  apple  matrices  for  (−)-cyflumetofen  and (+)-cyflumetofen at 50, 500, and 1000 μg/kg
Table  2.  Degradation  kinetic  constant  (k),  Half-life  (T 1/2 )  and  correlation  coefficient  (R 2 )  values  of  cyflumetofen in apple
+3

Références

Documents relatifs

The asymmetric addition of diazoacetate to styrene derivatives to give optically active trans cyclopropyl esters (ee up to 86%) was carried out in water (Nicolas et al., 2008) by

6a shows the schematic of a circularly polarized light detector based on chiral selective hot electron transfer in designed chiral plasmonic metamaterial in

Institute of Theoretical and Experimental Physios, Moscow, U.S.S.R. Nous introduisons des courants hydrodynamiques définis sur une algèbre de Lie, et nous discutons la chiralité.

therefore often referred to as ferroelectric liquid crystals (FLCs) whereas the term antiferroelectric liquid crystal (AFLC) is generally used for compounds exhibiting the SmC a

(Received 21 December 2018; revised manuscript received 25 April 2019; published 4 June 2019) Recent static experiments on twist effects in chiral three-dimensional

Due to the anticipat- ed low control of the allene chiral axis in the homologation step, we could affirm that the original axial chiral element, that is the cycloalkylidene moiety,

simulation of quenched SU(2), we show that the infrared logarithms expected in the chiral limit of complete QCD are not suppressed by the suppression of all internal

The chiral angle fluctuations can change the mean field experienced by the quarks and can produce excitations with properties of a pion and sigma field.. In the zeroth approximation